1. Field of the Invention
The present invention relates to means for supplying toner to photocopier devices, and in particular to a means for simultaneously filling and filtering the toner from a supply container into the feed container.
2. Description of the Prior Art
In xerography and modern high-speed data printers which operate in accordance with the principle of electrophotography, charge images are produced on a data carrier, for example, directly upon an intermediate carrier (photoconductive drum) or directly upon special paper, and are subsequently colored with a black powder (toner) in a developing station. When an intermediate carrier is used this toner image is then transferred to normal paper to which it is fixed. Generally a two-components developer composed of ferromagnetic carrier particles and toner particles is used for developing purposes. With the aid of a magnetic brush arrangement the developer is conducted past the charge image on the intermediate carrier to which the toner adheres as a result of electrostatic forces. An electro photographic copier which developes charge images in accordance with the described principle is disclosed, for example, in German As No. 21 66 667 corresponding to U.S. Pat. Nos. 3,784,297 and 3,883,240.
The coloring of the charge images of the intermediate carriers results in a continuous reduction in the toner concentration in the developer mixture in the developing station. Therefore it is necessary to continuously supply the developer mixture with dispensations of fresh toner. Because the toner consumption per time unit is extremely high in high-speed copiers and high-power data printers, such devices use a large volume toner feed container in order to avoid periods of inactivity during the refilling of toner. When the toner feed container becomes empty, the toner, which is usually supplied in managable containers, is filled into the feed container. When this takes place it is important that the toner should be transferred from the container into the feed container in such a way that no toner reaches the outside of the feed container.
For this purpose it has been proposed that the filling opening of the feed container should be shaft-like and should possess a cross-section which is such as to allow the upper part of the container, which contains the outlet openings, to be inverted into the filling opening.
A disadvantage of a device of this kind is that the bottles of toner must be emptied into the toner feed container by hand by means of shaking and tapping. Due to the unfavorable pouring properties of the toner, the operator must expend a considerable amount of time and labor in emptying the supply bottles. Furthermore, in the event of inefficient emptying, when the quantities involved are often considerable, residues of toner remain in the bottles. In addition it is possible for impurities of all sorts and sizes to enter the developing station through the filling openings of the toner feed container. Impurities present in the developer in the developing station can negatively influence the printed image and represent a high risk factor as regards damage to the photoconductive drum.